Since the plutonium is reactor grade, it has too much Pu240 and Pu242 to be used as a fission device. So, I would say Japan cannot make a bomb from those stockpiles. Of course, the reactor-grade plutonium could be used as a dirty bomb, but so could lead, mercury, other heavy metals and/or actinides.

Jim L.

It is highly likely that reactor grade plutonium can be used to make a viable device using modern techniques not available at the time of development of nuclear weapons.I don't really want to say more given Kirks well known views on such discussions - but advances in technology have largely eroded the distinction between the two.

The U.S. has called on Japan to reduce its high levels of stockpiled plutonium, a move that comes as the Trump administration seeks to convince North Korea to abandon its nuclear weapons, Nikkei has learned. The request was made by the U.S. Department of State and National Security Council ahead of next month's extension of a bilateral nuclear cooperation agreement, according to people familiar with the matter. Japan has about 47 tons of the radioactive element -- enough to produce around 6,000 nuclear warheads. Foreign and domestic critics have pointed to these reserves as a ready source of bomb-making material should Japan choose to become a nuclear weapons state. Plutonium production is banned in principle, but energy-poor Japan has been allowed to extract the material from spent nuclear fuel rods under the bilateral pact. Japan insists that it does not maintain plutonium reserves "without specified purposes." Critics in Japan and elsewhere, including China and some in the U.S. Congress, have expressed concern about the size of these stockpiles. Now, as U.S. President Donald Trump heads into a meeting with North Korean leader Kim Jong Un that Washington hopes will bring progress toward denuclearization, Japan's exemption form rules aimed at curbing the spread of nuclear weapons material may be called into question. The U.S. has asked Japan to impose a cap on its plutonium stockpiles. The Trump administration also wants to issue a joint statement, stating that Japan's plutonium supply is for peaceful use, when the nuclear cooperation pact is renewed, according to people familiar with the matter. In response, Japan's nuclear regulator is expected to adopt as early as this month a policy of reducing the stockpiles and not allowing them to exceed current levels. The start of operations at the Rokkasho reprocessing facility in northern Japan, which was intended to mass produce plutonium from spent nuclear fuel, is also likely to be delayed. These moves would amount to a de facto cap on the country's plutonium stockpiles. Tokyo "will respond in good faith to the [U.S.] request, but this will also require efforts by power companies," said a Japanese government source. "This isn't something that is going to happen overnight." The Japanese government has asked the Federation of Electric Power Companies, whose members include the country's nuclear plant operators, to reduce plutonium reserves. Two utilities in western Japan have been asked to consider using so-called mixed oxide fuel, a blend of uranium and plutonium, in reactors coming back online. But utilities have in principle used MOX fuel made with plutonium from the own plants. Moreover, with most of the country's reactors idle amid concerns over safety since the 2011 Fukushima disaster, the stockpiles look unlikely to fall soon. Some in the prime minister's office have expressed concern that the plutonium issue could doom Japan-U.S. nuclear agreement. The pact will renew automatically on July 16, but can be halted if if either side gives notice within six months. "If the U.S. calls off the deal, the foundations of Japan's fuel cycle will crumble," said a government source.

A better solution is to convert it to fluoride and use it as a fissile feed in nuclear reactors for power with fertile depleted uranium or, better still, thorium. Existing reactors could use it till MSRs come online as power reactors.

Japan plans to boost measures to curb surplus plutonium extracted from the reprocessing of spent fuel at nuclear power plants, including capping the country’s stockpile of the highly toxic material. The move followed the U.S. and other countries' calls for Japan to reduce excess plutonium in light of nuclear nonproliferation and the threat of terrorist attacks involving nuclear materials. The Cabinet Office’s Japan Atomic Energy Commission will incorporate the measures in the five-point basic nuclear policy expected at the end of this month, the first revision in 15 years. A reduction in the volume of plutonium held by Japan will also be specified in the government’s basic energy plan, which will be revised next month. Japan possesses about 10 tons of plutonium inside the country and about 37 tons in Britain and France, the two countries contracted to reprocess spent nuclear fuel. The total amount is equivalent to 6,000 of the atomic bomb that devastated Nagasaki in 1945. In the policy, announced in 2003, the government vowed not to possess plutonium that has no useful purpose. The government has pledged not to have surplus plutonium to the International Atomic Energy Agency. But the prospect for substantially curtailing the country’s plutonium stockpile is becoming increasingly murky as the Monju prototype fast-breeder project has been abandoned. The government decided in 2016 to decommission the Monju reactor in Tsuruga, Fukui Prefecture, which has seldom been in operation over the the past two decades due to a slew of problems. Monju was designed to use plutonium recovered from spent fuel from other reactors as a key component of the government’s nuclear fuel recycling program. Japan can reprocess spent nuclear fuel under the Japan-U.S. Nuclear Cooperation Agreement. The 30-year pact is expected to be automatically extended beyond its expiration on July 16. After the expiration, however, the pact will be scrapped six months after either Japan or the United States notifies the other side of its intention to do so. Foreign Minister Taro Kono has expressed concern about the "unstable" future of the agreement after July, and Japan has worked to meet a request from Washington to clearly spell out steps to reduce Japan’s plutonium stocks. The government's draft policy calls for allowing retrieval of plutonium strictly based on the projected amount to be used at conventional nuclear reactors as mixed plutonium-uranium oxide fuel, commonly known as MOX fuel. It will also step up oversight on utilities with the aim of reducing the amount of plutonium to a level allowing the nuclear reprocessing plant under construction in Rokkasho, Aomori Prefecture, and other facilities to operate properly. In addition, electric power companies will cooperate with each other in the use of MOX fuel, so that the amount of Japan’s surplus plutonium that is now overseas will be reduced. For example, Kyushu Electric Power Co. and Kansai Electric Power Co., two utilities that began using MOX fuel ahead of other utilities, will consider using more MOX fuel at their nuclear plants for the benefit of Tokyo Electric Power Co., whose prospect of bringing its Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture back on line remains uncertain. When the 2.9 trillion yen ($26.37 billion) reprocessing plant in Rokkasho goes into full operation, about eight tons of new plutonium will be added annually as Japan’s surplus plutonium. The Federation of Electric Power Companies of Japan, an electric power industry group, estimates that MOX fuel should be used at 16 to 18 reactors to keep the amount of Japan’s plutonium from rising. But of nine reactors that have resumed operations following the introduction of more stringent safety standards after the Fukushima No. 1 nuclear disaster in 2011, only four can use MOX fuel. The operation of the Rokkasho plant will likely be significantly curtailed even if it is completed amid that environment.

Japan will launch a public-private initiative to develop next-generation nuclear reactors that are safer and less expensive, hoping to spur a renewal of aging plants and keep atomic power as a viable energy source. The Ministry of Economy, Trade and Industry is in talks to create a forum within fiscal 2018 that will include power companies and reactor builders to kick off the project. The government's new energy plan, issued on July 3, positions nuclear energy as a crucial part of the nation's energy mix but does not spell out specifics as to how that can be achieved. By bringing together the expertise of various players, the government hopes to come up with a new technology that encourages construction and upgrades. After the 2011 Fukushima meltdown, all of Japan's reactors were suspended for safety inspections, and only nine, including those operated by Kansai Electric Power and Kyushu Electric Power, have restarted since. The government aims to have nuclear power make up 20% to 22% of the energy mix by 2030, a goal that would require having around 30 reactors running. Japan's large reactors -- some with a capacity of around 1 gigawatt -- require huge investment for construction and safety measures. Along with improving such large facilities, the public-private initiative will consider developing smaller reactors that generate around 100,000 to 300,000 kilowatts. Such reactors would cost several hundred billion yen (100 billion yen currently equals $898 million) to build -- significantly less than the roughly 1 trillion yen price tag for larger models. High temperature gas-cooled reactors are one option being considered. This type of reactor poses no danger of steam explosions during emergencies, unlike the water-cooled type that composes Japan's stock. Many of Japan's reactors have been running for decades, and new ones would feature new control technology and measures to contain the damage in a crisis. The economy ministry will recruit the country's big energy providers for the consultation body. Tokyo Electric Power Co. Holdings and Kansai Electricwill consider taking part if invited by the government. Mitsubishi Heavy Industries, Hitachi and other reactor makers will also be asked to join, as will the general contractors that would build the enclosing facilities. As Japan's nuclear reactors sit idle, decommissioning costs are growing as well. Even if new reactors are commercialized, companies will still bear the burden of dealing with their spent fuel -- a problem some see as too tough for the country's nine big power providers to handle separately. The economy ministry will also seek to have the public and private sectors work on hydrogen power, high-performance storage batteries, distributed generation and other technologies, aiming to develop a range of options for a stable energy supply to satisfy a public deeply skeptical of nuclear energy safety.

Tokyo is expected to call for understanding from Washington over Japan's growing plutonium stockpile as a nuclear cooperation agreement with the United States renews on Tuesday. The agreement authorizes Japan to reprocess spent nuclear fuel and recycle plutonium for use in reactors. The initial 30-year term ends on Monday. The pact is set to be renewed automatically the next day, because neither side objects to it. However, should either side object from now on, it will be rendered invalid 6 months from that point. The US is concerned about Japan's growing stockpile of plutonium amid difficulties over its reuse. The Monju prototype fast-breeder nuclear reactor, which was to serve as the core of Japan's nuclear recycling program, is set to be dismantled following a series of problems. Tokyo officials are likely to explain to Washington that they will try to reduce the amount of plutonium Japan is stockpiling, and also ensure better safekeeping. The US is expected to continue to demand a transparent nuclear energy policy from Japan, including a specific strategy for recycling nuclear fuel.

Japan and the U.S. have extended their nuclear pact as Tokyo pledged to work to reduce its plutonium stockpile to address Washington's concern. The 30-year pact agreed upon in 1988 has allowed Japan to extract plutonium and enrich uranium for peaceful uses even though the same technology can make atomic bombs. Without either side requesting a review, the pact was extended Tuesday with an option by which it can be terminated by either side giving six months' notice. The new condition, however, makes Japan's nuclear program more susceptible to U.S. policy. Foreign Minister Taro Kono told reporters that Japan must reduce the stockpile to keep the pact in place stably.

But in the 21 years between 1995, when a sodium leak at the Monju reactor forced a shutdown of operations, and 2016, when the government formally decided to scrap the facility, Japan's plutonium stockpile increased threefold.

"If the government is to continue its nuclear fuel recycling program, it will be insufficient to only revise its plutonium usage plan," Sakata said. "The only option available will be to show the world through specific results that it is serious about not holding surplus plutonium."

Under the elusive nuclear fuel cycle policy, plutonium extracted from spent fuel removed from nuclear reactors is to be converted into plutonium-uranium mixed oxide (MOX) fuel to be used either in fast-breeder reactors or in conventional nuclear plants. But Monju, the nation’s sole fast-breeder reactor and once deemed a prototype for a dream technology for this resource-scarce country because it produces more plutonium than it consumes as fuel, remained mostly idle after it reached criticality for the first time in 1994. It suffered a sodium coolant leak and fire in 1995 and a subsequent series of other problems, until the decision was made in 2016 to finally pull the plug for good.

The use of MOX fuel in conventional reactors, deemed a substitute way to consume the plutonium stockpile, has also not proceeded as expected. The government earlier planned to have MOX fuel used at 16 to 18 reactors across the country by 2015. But the restart of nuclear power plants idled in the wake of the 2011 meltdowns at Tokyo Electric Power Co.’s Fukushima No. 1 plant remains slow. Only four of the nine reactors that have so far been brought back online are capable of using the costly MOX fuel, and only in small amounts.

While the consumption of plutonium as reactor fuel stagnates, the reprocessing of the spent fuel to extract plutonium has also hit a snag. Completion of a reprocessing plant in Rokkasho, Aomori Prefecture — on which more than ¥2 trillion has already been spent — has been delayed for years due to a series of technical glitches. But once completed, the reprocessing plant supposedly will be able to produce up to 8 tons of plutonium annually, raising the specter of further increasing the stockpile of unused plutonium if its use does not pick up.

TEN years after the incineration of Hiroshima and Nagasaki by American nuclear bombs, Japan embraced “atoms for peace”, a policy of civilian nuclear power championed by Dwight Eisenhower, America’s president. The dowry in this unlikely cold-war marriage of convenience was six kilograms of enriched uranium, which Japan used to seed a nuclear-energy programme that would eventually provide it with about a third of its electricity. In 1988 Japan was permitted—under tight international controls—to enrich uranium and extract plutonium, employing the same technology used to make nuclear bombs. This month the two governments extended the 1988 agreement. Japan has now amassed 47 tonnes of plutonium, enough to make 6,000 bombs. What is Japan doing with so much plutonium?

Plutonium is at the heart of Japan’s tarnished dream of energy independence. Spent fuel from nuclear reactors can be reprocessed to extract plutonium, which is then recycled into mixed oxide, or MOX, fuel. This was intended for use in Japan’s reactors but most of its nuclear power plants have been offline since the 2011 Fukushima disaster. Tougher safety checks have failed to reassure the nuclear-phobic public that the reactors can be restarted. And Japan’s nuclear-energy fleet is ageing. Taro Kono, Japan’s foreign minister, has admitted that this situation is “extremely unstable”.

Japan’s status as a plutonium superpower is increasingly under scrutiny. The government says it has no intention of building a bomb. But China and other countries question how long it can be allowed to stockpile plutonium. Analysts worry about a competitive build-up of plutonium in Asia. Moreover Japan’s stock, which is weapons-grade, is reprocessed and stored in France and Britain. It is moved across the world in heavily armed convoys. America says those shipments and the storage of plutonium in civilian sites present a potential threat to non-proliferation goals: they could be redirected to make weapons, or targeted by terrorists. It is nudging its ally to start reducing the hoard.

One solution might be to fire up the Rokkasho plant, the centerpiece of Japan’s nuclear recycling policy. Rokkasho, in Japan’s snowy north, could produce eight tonnes of plutonium a year. But it is three times over budget and two decades late (it is now supposed to open in March 2022). Even if it someday works, most of the reactors supposed to use its MOX fuel are offline. America could tighten the screws or even terminate the 1988 pact (a clause allows it to do so) though the robust bilateral alliance makes that very unlikely. That means Japan must either find a way to bury its cache underground—a huge and costly feat of engineering—or pay countries such as Britain and France to store it overseas, perhaps permanently. The most likely scenario is a continuation of the status quo, unstable as it is.

They've been speeding up recert work for existing reactors because this summer has been killer (new record national high temp). TEPCO is even allowing existing coal and gas thermal plants to exceed standard max output limits to keep up with grid demand, and a couple of mothballed coal plants have been restarted.

More than 30 years ago, when its economy seemed invincible and the Sony Walkman was ubiquitous, Japan decided to build a recycling plant to turn nuclear waste into nuclear fuel. It was supposed to open in 1997, a feat of advanced engineering that would burnish its reputation for high-tech excellence and make the nation even less dependent on others for energy. Then came a series of blown deadlines as the project hit technical snags and struggled with a Sisyphean list of government-mandated safety upgrades. Seventeen prime ministers came and went, the Japanese economy slipped into a funk and the initial $6.8 billion budget ballooned into $27 billion of spending. Now, Japan Nuclear Fuel Ltd., the private consortium building the recycling plant, says it really is almost done. But there is a problem: Japan does not use much nuclear power any more. The country turned away from nuclear energy after the 2011 Fukushima disaster, and only nine of its 35 reactors are operational. It is a predicament with global ramifications. While waiting for the plant to be built, Japan has amassed a stockpile of 47 metric tons of plutonium, raising concerns about nuclear proliferation and Tokyo’s commitment to refrain from building nuclear arms even as it joins the United States in pressing North Korea to give up its arsenal.

Now that plan A for energy independence from recycled plutonium has failed, it is time to try a plan B. It could be use of a thorium- plutonium MOX in their reactors. The pluses of the plan areLonger reactor life of the fuel. It results from higher conversion of thorium to fissile U233.Possible progress to breeders like the Shippingport.

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